Two-stroke internal-combustion engine



March 27, 1928. 1,664,086

s. D. OLSEN TWO-STROKE INTERNAL COMBUSTION ENGINE Filed Rug-19, 1925 2 Sheds-Sheet 1 W c I Z k March 27, 1928. 1,664,086

S. D. OLSEN ,TWO-STROKE INTERNAL COMBUSTION ENGINE Filed Aug. 19, 1925 2 Sheets-Sheet 2 i 20 inder, this being provided Patented Mar. 27, 1928.

- UNITED STATES PATENT OFFICE.

amen no KI OLSEN, OF LONDON, ENGLAND, ASSIGNOiR Td TNE OLSEN ENGINE SYNDI- ,CATE LIMITED, LONDON, ENGLAND, A BRITISH- COMPANY.

TWO-STROKE INTERNAL-COMBUSTION ENGINE.

Application filed August 19, 1925, Serial No. 61,218, and in Great Britain September 5, 1924.

I This invention has reference to internal combustion engines and is designed to provide an engine of the two-stroke valveless type with opposed pistons, which shall be 5 very simple and cheap in construction as well as economical in fuel and be capable of c working with a sparking plugand fuel injector instead of a carburettor.

The construction of engine to which the invention applies more particularly is that in which the. opposed pistons or plungers, instead of operating through cranks act between the edges of cylindrical (or drum like) cams at the ends of the cylinders, and in lewhich the main sh'a between the cylinders. v A-feature of the invention is that these pistons also serve as the valves for controla a ling the inlet and exhaust ports of the cylfor by the suitable shaping of the cam-edges or surfaces, so dispensing. with the use of both ordinarylift valves and timing gear, whilst however -"still allowing of a super-charge of air being introduced into the cylinder.

I Another feature of the invent ,the mouths of the c linders and pistons are deeply slotted to a ow them to project as far as possible over the cylindrical cams at p the ends of the cylinders.

. I A. further feature of the invention is that the ports of the workin chamber of the cylinder are very large an are practically completel annular or extend all round each end t ereof, whilst they also lead out into large p extent to sllence the exhaust.

In order that the invention may be clearly understood. and readily carried into effect: reference willnow be had' by way of example -to. the accompanying diagrammatic drawings,'in which? Fig. 1 is "a hor zonta 15-1 of Fig. 3, and

Fig. 2 is'a side viewof a two cylinder-engine according to the invent on, adapted to work on the two-stroke principle without a carburettor;

l section on the line Fig. 3 is a central transverse section through Fig. 1. v

v In the example illustrated, a a, are the cylinders which are provided. with; o positely ,moving pistons b. These cyhn are are formed or fitted parallel with each other in 55 a suitable casmg a, prov ft lies parallel with and 3) ion is that" assages which act to'a considerable ided with water jackets (l, and have inlet and exhaust ports 6 and e. The casing has 'two hollow end covers 7' to enclose or house the cams at the centres of which covers are provided ballbearlngs g for-the main shaft k, that is to say the shaft carrying the cylindricalvend cams i which serve to set up rotary motion lnsteadof cranks. V

(1 (P. are the inlet and outlet pipes for the cooling'water for the jackets d. j The main cams i situated in'the ends of the casin somewhat resemble two, cups facing eac other, each having a web 11 and a hub j mounted on the shaft h. The said,- cams in fact form cylindrical'flanges around 'these hubs j being wide at one side and narrow' at. the other, so that their shape cor-. responds to (or provides for) a single inand-out stroke of the pistons b in each revolution. The hubs 7' are thickened at one side to counterbalance the wider sides of the cams. v 3

, Each of the cylindrical or drum-likevend cams has an upstanding lip ktthe inner side of which forms the main or workin-g-cam-. track, while the outer side forms a shallower parallel auxiliary track. The pistons 12 are of the ordinary hollow-type, and each carries a air of bevelled anti-friction rollers Z, m between which the aforesaid lip k of the cam lies, so that they act onv both sides of the latter. j These rollers are carried by axle pins l, 7m. secured in the mouth of the istons, as shown, the axle 1 being inclined and the rollers I having anti-friction-bearings l;

The outer roller m is smaller thanthe other' or main roller as it is merely to enable the cam to guide or draw the piston along when stantin up, the engine. A small gap, e -way. or gate k is. formed in th'e'li It; or instance at the neutral or flat portion of the'cam track where it will not effect the running. This gap need onl be as wide asthe smaller or aux- 10o 'iliary ro ler. It is to enable this latter roller to pass through if it be desired to take the cam ofi the end of the shaft to permit the pistons to be drawn outor for other par steady and effective for the pistons 110 6. Corresponding recesses b are formed in the mouths of the pistons.

. The pistons come fairly close to ether (see bottom of Fig. 1) when forced inward by 8 the main cam z, and the space between them forms the compression and explosion chamher, a sparkingplug 0 and an injector device t being inserted, through the side .wall of each cylinder into the compression chamber. The plugs are connected to a magneto which may be worked by a skew-gear q. as shown.

The fuel injector t is similar to the double acting injector described in my pending United States patent application Serial'No. 16,457 filed 18'March 1925.

Each of these injectors is operated by a cam uon the main shaft, acting counter to a spring through a bell-crank lever 11 pivoted on a short axle v. The injectors t draw the fuel oil from the float chamber on through a regulating valve 'w and inJect it into the cylinders practicallyas vapour. The injection takes place after the lston has closed the outlet and inlet ports. The float chamber w may be mounted in any suitable way. For instance it may be secured to a part of the chassis 112 as; shown, or to a bracket on the engine frame. The regulating'valve has a se arate pipe connection w: leading to each in ector. l

A hand-lever a: pivoted also on v is provided for working the levers v and so. hperthe vera: as a heel 0: adapted to engage and operate the levers 'v alternately.

v The upper end 0 of each lever '12 is forked, the tubular guide I) of the injector stem t passing through such fork.

The said "fork acts against the lower end of the spring-barrel t in order to lift the injector plunger t and. compress the spring."

The group of ports e e at-each end of the cylinder form ractically one large annular port. The in et ports 6 .(on the right) open nto an annular chamber or compartmentv 1' in ,communicationwith a main in let or flanged opening r leading in from the air compressor or blower. The exhaust ports a (on the left) communicate with a similar chamber 8' leading to the discharge outlet s which chamber owingftoits large capacity acts as a silencer.

The hain or end cams z' are so shaped as that the pistons uncover the exhaust ports in-such a way as to allow the spent gases toescape 811% a fresh supply of air frdm thev blower. to ta e their place, after whichsaid exhaust ports are closed whilst the superto charge isbeing admitted throu h the inlet rts, which remain opexr later t an the exaust ports. ,In more detail the action of the pistons with regard to the ports at each end of the y a cyhnders 15 as follows;

.to' revolve by force of the pistons as they sting the in'ectors at starting. .To this'end (a) Starting with the pistons 12 in the innermost position (seebottom of Fig. 1) explosion takes place between them by means q of a sparking plug and" the cams are caused separate. One piston, say the left-hand one at or near the end ofthls stage (see -to of -Fig. 1) opens the exhaust ports. e the 1nlet or scavenging ports e at.the other end being still covered and closed "however by the rightand position. a (b) 'After the pressure in the cylinder is relieved both pistons separate a little further, and the right-hand piston completely uncovers the inlet or scavenging ports so that the scavenging a r can enter and scav enge thecyhnder.

(a) At the next instant the left-hand pison advances, and com letely closes the exhaust ports, but the right-hand piston still uncovers the inlet or scavenging ports so as i to allow the supercharge to be admitted. v

(d) The inlet'ports are then closed, fuel is injected into the cylinder and both pistons advance towards each other; at their innermost position the charge is compressed and ready for the next exp osion, and so on.

Obviously the arran ements above referred to may be modi ed in various wa s incarrying the invention into practice wit out departing fromthe general naturethereof. u 1

I claim:-

1. In an internal-combustion engine, the combination of stationary cylinders open at both ends and parallel with the main shaft, opposed pistons in said cylinders acting also as valves to control the air inlet and the ex.-

haust portsjrevo'lving cams fast on the main shaft opposite the ends of the cylinders, slotted mouths on the cylinders and pistons, whichmouths overlap the cams, rollers mounted at the mouths of the pistons and engaging opposite sides of the cam-tracks, a casm co rising a water jacket portion 1 for t e cyhnders' and end-covers enclosing the cams, and bearings in said end-covers for the main shaft, substantially as described.

2. In a two-stroke internal-combustion engine, the combination of a main. shaft, end cams, thereon; cylinders open at both ends parallel therewith and overlapping the cams, large inlet and exhaust ports extendmg practically all round the cylinders, pistons in said cylinders, and cams 'on said shaft between which said pistons work so as to approach andrecede from each other simultaneously, a water-jacketed casing with covers for the cams at each end thereof, bearlngs in said covers for the main shaft, and accessible (ggilsring on said shaft for controlling the a sion of the fuelcharges, substantially as described.

In a two-stroke internal-combustion engme, the combination of a m n Shaft,

cylinders and acting as valves to control the air-inlet and the exhaust ports, rollers car ried on inclined axles inthe mouths of said pistons and engaging the inner sides of tracks on the cams, said cam tracks being formed by upstanding lips on the cams,

outer rollers also carried by the projecting mouths of the pistons and engaging the outer sides of the cam tracks, and slots or gaps in said tracks through which the rollers can pass when withdrawing the pistons,

substantially as described.

4; In a two-stroke internal-combustion engine,the combination of a revolving main shaft, revolvingtcams fast on said shaft, stationary cylinders parallel with said main shaft and having their mouths overlapping the cams, large ports in both ends of the cylinders extending practically all round said ends, opposed pistons in said cylinders, bevelled rollers oninclined shafts in the mouths of said pistons, housing covers for the cams-secured to the opposite ends of the cylinders, a water-jacketed easing between said end covers, gearing on the shaft for controlling the fuel supply, and a hand-lever for operating the; fuel-supply devices at starting,substantially as described.

5,. In an internal-combustion engine, the combination of a niain shaft, 'end cams thereon, cylinders arranged parallel with the main shaft and open at both ends, which ends are slotted and project beyond the cams,

pistons with slotted mouths to permit them 6 also'to overlap said cams, two sets, of rollers carried in the mouths of said pistons'and vengaging-opposite sides of the cam-tracks,

a water-jacketed casing containing said cylindersandhaving spaces in it to receive the exhaust gases, end-covers on said casing to house the cams, bearings at the centres of said covers to carry the main shaft, and accessible gearing on said shaft for working the magneto and the fuel injectors, substantially as described In testimony, whereof I afiix iny signature.

SIMON DoKK OLSEN. 

